The Extract from the Patek Philippe archives confi rms that this watch was sold on October 23rd, 1953 and that the dial is enamel with applied gold hour markers. Reference 2526 was introduced in 1953 and was the fi rst self-winding production wristwatch ever made by Patek Philippe. The watch was designed with the celebrated 12'''-600 AT caliber, the fi rst 2526 bearing the serial number 760,000. The Ref. 2526 is a most appealing wristwatch and is highly sought after by collectors. There have been four generations of this model which have evolved as follows: - 1st generation: domed screw back, beige enamel dial with applied indexes. The enamel is fl ared around the holes which hold the indexes, the central hands and the subsidiary seconds hand. - 2nd generation: domed screw back, beige enamel dial with applied indexes. The indexes are inlaid in the enamel surface; the enamel is fl ared around the holes which hold the central hands and the subsidiary seconds hand. In this particular series, only a very few examples were made with a black dial and even fewer with Breguet numerals. - 3rd generation: identical to the 2nd generation but with a practically fl at screw back. Very few examples of this series were produced with a black dial, and only one with a black dial and Breguet numerals is known to date. - 4th generation: practically fl at screw back, beige enamel dial with applied indexes. The indexes are luminescent and inlaid in the enamel surface; the enamel is fl ared around the holes which hold the central hands and the subsidiary seconds hand.